The present invention relates to filler tube assemblies for fuel tank installations of the type having a fuel vapor recirculation tube ported to the upper end of the filler tube in the enlarged nozzle receiving end. Fuel vapor recirculation tubes are employed in motor vehicle fuel tank filler tubes in order to provide vapor recirculation during refueling from a nozzle inserted in the filler tube with a mechanical seal provided about the nozzle. The recirculated vapor provides a make-up flow below the nozzle seal to prevent the flow discharging from the nozzle from creating a vacuum in the filler tube and prematurely activating the automatic nozzle shutoff.
In the aforesaid fuel tank filler tube installations having a vapor recirculation tube attached to a port in the filler tube below the nozzle seal, problems have been encountered where liquid fuel rising in the filler tube, upon the tank becoming filled, has resulted in liquid fuel entering the vapor recirculation tube and flowing into the vapor vent system. Liquid fuel in the vapor vent system can result in blockage of the vapor vent lines by fuel trapped in low regions or in some cases liquid fuel entering into the vapor storage canister causing degradation of the vapor storage medium in the canister.
Thus, it has been desired to provide a way or means of protecting a fuel vapor recirculation system from flow of liquid fuel into the vapor lines and to do so in a manner which is simple and low in cost and does not require substantial reworking or retooling of the fuel tank filler tube.